Internal mic's will pick up mostly lows, you will lose the dynamics coming from the head along with the higher frequencies. I have experimented with Djembe's in my studio and I get the best results mic'ing both the top of the drum and putting one off axis near the bottom of the drum. With that said, I do not think it is best for your situation. Sounds like you are going to be recording 2 channels, yes? I would go with muj's suggestion optimally for 2 channel, but if you are working with sm57's you may need to spend a little more time moving mic's and people around until you get the most balanced sound. If you are looking to spend some money on mic's but want to stay cheap, look at the Studio Projects brand, they have large diaphragms, etc, that are as cheap as it gets while retaining decent quality. Another option would be to use 4 or 5 57's and get a cheap mixer, line out of the mixer into the 2ch recorder, also, I would throw a "room" mic in there to add a little ambiance.